The Lockheed Martin VH-71
As a sketch, this plane looked great. In 2002 Augusta Westland and Lockheed Martin began marketing the plane in the US and it seemed like it was going to be great! The Marine Corps even recorded it be used by the President. However, they changed the price from $6.1 billion to $11.2 billion several years later, and this was not realistic
The Bristol 188
Whatever field you work in, it’s important to be in line with your competitor. In 1947, Chuck Yeager created the Bell X-1, and this inspired others to create a plane resembling it. The British made their rendition called the Bristol 188, but it was flawed. It had a leaking fuel tank and needed a ground speed of 300 MPH to actually take off.